Answers are grounded in this paper and cite their sources.
A sensitive differential mercury manometer is described. Mercury surfaces in two arms of the manometer form plates of condensers connected to two nearly identical oscillator circuits. A change in pressure produces a change in the beat frequency of the oscillators which is measured by comparison on an oscilloscope with the output of an audiosignal generator. For 0<Δp<0.02 cm an accuracy of 0.1 to 0.2 micron of mercury is obtained. For Δp between 0.02 cm and the maximum measurable with the manometer (approximately 0.25 cm) the accuracy appears to be 0.1 percent or better.
No takes yet. Share an insight, caveat, or question.
Los et al. (1951) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: